This study's main objectives are to determine whether persistent otitis media with effusion (OME) in the first 3 years of life results in lasting impairments of speech, language, cognitive, or psychosocial development, and if so, whether they are prevented or lessened by prompt tympanostomy- tube placement (TTP). From 2 hospitals and 6 pediatric practices 6391 well infants aged <2mo were enrolled. Middle-ear status and hearing are monitored. Up to age 3, children who reach specified criteria regarding persistent OME are randomized to undergo TTP either promptly or after a defined extended period of OME persists. Detailed developmental tests are administered at ages 3, 4 and 6 yr to all subjects who had met randomization criteria and to a sample of others representing a spectrum of OME experience. Analyses of results will enable determinations whether associations exist between early OME and later developmental impairments; if so, whether the associations are causal; and whether prompt TTP is effective in preventing or lessening such impairments.